All Sand Veil Pokemon are Uber if they have Sand Veil as their ability: Sandshrew, Sandslash, Diglett, Dugtrio, Gligar, Gliscor, Cacnea, Cacturne, Gible, Gabite, Garchomp, Geodude, Graveler, GolemPhanphy, Donphan, Lavitar, and Stunfisk
All Snow Cloak Pokemon are Uber if they have Snow Cloak as their ability: Swinub, Piloswine, Mamoswine, Glaceon, Froslass, Cubchoo, Beartic, Articuno
All Moody Pokemon are banned from the metagame if they have Moody as their ability: Remoraid, Octillery, Smeargle, Snorunt, Glalie, Bidoof, Bibarel
Any Pokemon holding Soul Dew is Uber, but Latios and Latias are the only ones to make use of it.
Snover, Vulpix, Hippopotas are OU if they are using their weather inducing ability.
Any Pokemon with Shell Smash and Baton Pass are UU if they have those two moves on their set: Gorebyss, Huntail, and Smeargle
Any unreleased Dream World Ability instantly goes to the DW tiers.
http://www.smogon.com/forums/showthread.php?t=3472966
